Different sorts of signals may be transmitted through telecommunication systems. Among these signals are voice signals, facsimile signals, data signals, video signals etc. Furthermore, in today networks, signals may also be classified by their quality, a characteristic that is used to differentiate between different quality of services.
Various types of telecommunication systems are known in the art and in the marketplace for interconnecting telephone communication trunks to a transmission network. One type of such systems is known as Digital Circuit Multiplication Equipment (to be referred to hereinafter as “DCME”) systems.
In order to use network available resources as efficiently as possible, many solutions were suggested in the past. One such example is the use of optimal ADPCM algorithm in DCME systems, where this algorithm is adapted for transmission of compressed voiceband data. This solution allows achieving a typical compression rate of 2:1. However, when taking into account that the compression rate of the DSI and the ADPCM algorithms for speech is 6:1, it is understood why even such an improved algorithm presents a bottleneck in these systems. In the recent years, the use of facsimile machines is constantly growing, and since facsimile signals are transmitted via DCME systems when compressed as voiceband data, the overall compression rate that can be achieved for DCME systems approaches 3:1 ratio. When using more advanced encoding algorithms such as LD-CELP and CS-ACELP, higher compression rates may be achieved, as the typical overall compression rates are 8:1 and 16:1, respectively. Nevertheless, in view of the developing traffic load in telecommunication systems, there is constant striving for better utilization of the network resources available, which in turn will allow to reduce communication costs while maintaining required qualities of service.
Therefore, it is understandable why solutions for better utilization of resources both in TDM and non-TDM systems, such as IP systems, are to be found.